The noise Jamie makes against Sora's mouth at the tongue action and the touch of fingers along the curve of his back is particularly undignified and therefore a sign of how pleasurable he finds it all. Perhaps unsurprisingly for someone who shuns physical contact so much during his day-to-day life, being touched in such an intimate way is intense, almost overwhelming, and he responds accordingly. Pretty soon he's squirming beneath Sora, trying for leverage of his own, his hand wandering from the back of Sora's head down to his jaw and the side of his neck like he's trying to touch him everywhere at once.

Two wriggling teenage boys on a sofa is probably a recipe for disaster, but Jamie's too drunk and too swept up in his emotions to care about anything but the way Sora's making him feel.